Netext Working Group F. Abinader, Ed.
Internet-Draft Instituto Nokia de Tecnologia
Intended status: Standards Track S. Gundavelli, Ed.
Expires: July 13, 2012 K. Leung
Cisco
S. Krishnan
Ericsson
D. Premec
Unaffiliated
January 10, 2012
Bulk Binding Update Support for Proxy Mobile IPv6draft-ietf-netext-bulk-re-registration-10
Abstract
For extending the lifetime of a mobility session, the Proxy Mobile
IPv6 specification requires the mobile access gateway to send a Proxy
Binding Update message to the local mobility anchor on a per-session
basis. In the absence of signaling semantics for performing
operations with group specific scope, it results in significant
amount of signaling traffic on a periodic basis between a given
mobile access gateway and a local mobility anchor. This document
defines optimizations to the binding update and revocation operations
in Proxy Mobile IPv6 for performing operations with group specific
scope with the use of a group identifier.
Status of this Memo
This Internet-Draft is submitted in full conformance with the
provisions of BCP 78 and BCP 79.
Internet-Drafts are working documents of the Internet Engineering
Task Force (IETF). Note that other groups may also distribute
working documents as Internet-Drafts. The list of current Internet-
Drafts is at http://datatracker.ietf.org/drafts/current/.
Internet-Drafts are draft documents valid for a maximum of six months
and may be updated, replaced, or obsoleted by other documents at any
time. It is inappropriate to use Internet-Drafts as reference
material or to cite them other than as "work in progress."
This Internet-Draft will expire on July 13, 2012.
Copyright Notice
Copyright (c) 2012 IETF Trust and the persons identified as the
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Internet-Draft Bulk Binding Update Support January 20121. Introduction
The Proxy Mobile IPv6 base specification [RFC5213] requires the
Mobile Node Identifier option to be present in the mobility signaling
messages, such as in the Proxy Binding Update and Proxy Binding
Acknowledgement messages. It essentially limits the operational
scope of the binding update operation to a single mobility session.
These signaling messages lack the capability to identify a group of
mobility sessions, so the binding update and revocation related
operations can be performed on all the mobility sessions that are
part of that group.
There is a need to have semantics for associating a group identity to
a mobility session, so the scope of the binding update and revocation
related operations can be extended to all the mobility sessions
identified by the group identifier. The group identifier therefore
provides a considerably improved mechanism for protocol operations
which would otherwise require multiple atomic transactions on a per
mobility session basis. Following are some of the use-cases where
the group identifier can be used.
o For extending the lifetime of a mobility session, the mobile
access gateway periodically sends a Proxy Binding Update message
to the local mobility anchor on a per-session basis. This process
can be optimized by allowing the mobile access gateway to send a
single Proxy Binding Update [RFC5213] message for a group of
mobility sessions, identified by a group identifier. The local
mobility anchor upon accepting the request can update the lifetime
of all the mobility sessions that are part of that group.
o A local mobility anchor, or a mobile access gateway service hosted
on blade architecture system, on detecting a failure of a specific
service card, can potentially request the peer to revoke all the
sessions that are hosted on that service card, identified by a
common group identifier. Potentially, a single Binding Revocation
Request [RFC5846] message carrying the group identifier can be
used to revoke all the sessions hosted on that service card, which
otherwise needs to be handled on a per-session basis.
This document defines a new mobility option, Mobile Node Group
Identifier option, and the extensions to binding update and binding
revocation related procedures for performing binding operations with
group specific scope.
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Internet-Draft Bulk Binding Update Support January 20122.1. Conventions
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
document are to be interpreted as described in RFC 2119 [RFC2119].
2.2. Terminology
All the mobility related terms used in this document are to be
interpreted as defined in the base Proxy Mobile IPv6 specifications
[RFC5213] and [RFC5844]. Additionally, this document uses the
following abbreviations:
Bulk Binding Update
A binding update operation that has group specific scope. A
binding operation is associated with a specific mobility session.
However, a Bulk binding update operation is associated with
multiple mobility sessions. This operation is not relevant for
new mobility session creation.
Bulk Binding Update Group
A group of mobility sessions that are part of the same logical
group and therefore share a common group identifier. This group
is the bulk binding update group. This bulk binding update group
is maintained by both the mobile access gateway and the local
mobility anchor, and the grouping logic is local to that node. A
mobility session therefore can be identified by two bulk binding
update group identifiers, one specific group created by the mobile
access gateway and the other specific group created by the local
mobility anchor. The bulk binding update group identifiers are
exchanged as part of the initial mobility session creation. The
mobility entities thereafter can perform binding update related
operations such as lifetime extension and revocation operations on
an entire bulk binding update group, identified by a group
identifier.
3. Bulk Binding Update Overview3.1. Motivation
In a typical Proxy Mobile IPv6 domain, a local mobility anchor serves
multiple mobile access gateways and the capacity of that node with
respect to the number of mobility sessions that it can host is quite
high, typically in the order of few millions. As the number of
mobility sessions hosted by a local mobility anchor goes up, so is
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the amount of signaling traffic related to periodic binding update
related traffic.
The currently specified approach of binding update procedure for
extending the lifetime, where the mobile access gateway is required
to send a unique binding update message for each mobility session,
even when there is no change to the session state is inefficient or
sub-optimal. These periodic binding update messages consume
significant amount of network resources, both in terms of processing
power and in terms of network bandwidth and at both the peers. There
is an opportunity to optimize the signaling procedures by allowing
the local mobility anchor and the mobile access gateway to perform
bulk binding update operations. This document specifies extensions
to Proxy Mobile IPv6 signaling for performing binding update and
revocation operations on a group of mobility sessions. These
extensions do not take away the existing functionality of performing
binding operations on a single mobility session.
3.2. General Operation
The bulk binding update mechanism specified in this document allows
the mobile access gateway and the local mobility anchor to perform
binding update and revocation operations on a group of mobility
sessions. As part of the initial signaling during mobility session
establishment, the local mobility anchor and the mobile access
gateway exchange the respective bulk binding update group identifiers
for that mobility session. Subsequently both the peers can perform
bulk operations on those groups by presenting the bulk binding update
group identifier in the signaling messages.
A mobile access gateway when sending a Proxy Binding Update message
after detecting a new mobile node on its access link, can request the
local mobility anchor to assign a bulk binding update group
identifier for the mobile node's mobility session. This is indicated
by setting the (B) flag in the Proxy Binding Update to a value of
(1). The mobile access gateway will also assign a bulk binding
update group identifier (or it may assign a default bulk binding
update group - ALL-Sessions) and include that in the Mobile Node
Group Identifier option.
The local mobility anchor upon accepting the request will group the
mobility session to a specific bulk binding update group (or it may
assign it to the default bulk binding update group - ALL-Sessions)
and return this bulk binding update group identifier in Proxy Binding
Acknowledgement message. It will also set the (B) flag in the Proxy
Binding Acknowledgement message to a value of (1). The bulk binding
update group identifier is carried in the Mobile Node Group
Identifier option, described in Section 4.3.
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Once the bulk binding update group identifiers are exchanged, the
local mobility anchor and the mobile access gateway can perform
binding operations on those entire groups, by including the bulk
binding update group identifier in the signaling messages. For
example, the mobile access gateway can extend the lifetime of all the
mobility sessions that are part of a group by sending a single Proxy
Binding Update message with that bulk binding update group
identifier. Similarly, the local mobility anchor can revoke all the
mobility sessions that are part of a group, by including that group
identifier in the Proxy Binding Revocation message.
Figure 1 explains the operational sequence of the bulk binding update
and revocation operations on a group of mobile nodes, MN1, MN2 and
MN3.
MAG LMA
(1) | |
MN1-------| (2) PBU |
|--------------------------->|
| * (3)
| (4) PBA |
|<---------------------------|
* (5) |
(6) | |
MN2-------| |
* (7)........................|
(8) | |
MN3-------| |
* (9)........................|
| |
| (10) PBU |
|--------------------------->|
| * (11)
| (12) PBA |
|<---------------------------|
* (13)
| |
| (14) BRI |
|<---------------------------|
| * (15)
| (16) BRA |
|--------------------------->|
* (17) |
| |
Figure 1: Exchange of Group Identifier
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o (1) to (2): MAG detects the mobile node's (MN1) attachment to the
access link. The MAG groups the mobile node to a specific bulk
binding update group, (M1). The MAG notifies this group
identifier to the LMA by including it in the Mobile Node Group
Identifier option of the PBU message.
o (3): The LMA upon accepting the PBU, creates a mobility session
and groups the mobility session to a specific bulk binding update
group, (L1). The LMA updates the mobile node's BCE entry to
include the bulk binding update group identifier, (L1) and the
bulk binding update group identifier presented by the MAG, (M1).
The LMA also notifies the MAG about the bulk binding update group
identifier (L1), by including it in the PBA.
o (4) to (5): The MAG upon receiving the PBA updates the BUL entry
for that mobility session to include the bulk binding update group
identifiers (L1) and (M1). At this point, both the LMA and MAG
are aware of the mobile node's bulk binding update group
identifiers assigned by the peers.
o (6) to (9): The above steps (1 through 5) are repeated here for
MN2 and MN3, details are omitted. At the end of step (9), the MAG
completes the signaling with the LMA. The MAG assigns the mobile
nodes, MN2 and MN3 to bulk binding update groups, M1 and M2
respectively, while the LMA assigns them both to the same to the
bulk binding update group, (L1).
o At this point, LMA has assigned MN1, MN2 and MN3 to the bulk
binding update group of (L1), while the MAG has assigned MN1 and
MN2 to the group (M1) and MN3 to group (M2). Both the peers can
now perform binding operations on a group of mobility sessions
identified by the respective bulk binding update group identifier.
o (10) to (13): The MAG sends a periodic binding update message for
extending the lifetime of all the mobility sessions that are part
of the bulk binding update group, (M1). It includes the bulk
binding update group identifier, (M1) in the PBU. The LMA upon
accepting the PBU, extends the lifetime of both MN1 and MN2, which
are part of the group (M1).
o (14) to (16): The LMA decides to revoke all the sessions that are
part of bulk binding update group, L1. The LMA sends a BRI
message with the bulk binding update group identifier, (L1). The
MAG upon accepting the BRI message revokes all the MN1, MN2 and
MN3 mobility sessions, which are part of that bulk binding update
group, (L1).
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Internet-Draft Bulk Binding Update Support January 20124. Message formats
This section identifies the extensions to Proxy Mobile IPv6 signaling
messages that are required for supporting this specification.
4.1. Extensions to Proxy Binding Update Message
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Sequence # |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|A|H|L|K|M|R|P|F|T|B| Reserved | Lifetime |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
. .
. Mobility options .
. .
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 2
A new flag, Bulk-Binding-Update (B) flag is defined in the Proxy
Binding Update message specified in [RFC5213]. The bit-value of
Bulk-Binding-Update (B) flag in the flags field of the message will
be (IANA-1).
If the Bulk-Binding-Update flag (B) is set to a value of (1), it
informs the local mobility anchor to enable bulk binding update
support for the mobility session associated with this message. If
the (B) flag is set to a value of (0), the local mobility anchor MUST
exclude the mobility session associated with this message, from any
bulk binding related operations and any binding update, or binding
revocation operations with bulk specific scope will not be relevant
to that mobility session.
This flag is relevant only for Proxy Mobile IPv6 and therefore MUST
be set to value of (0), when the (P) flag is set to a value of (0).
All other fields in the Proxy Binding Update message and the mobility
options that can be carried in the message confirm to the respective
specifications.
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Internet-Draft Bulk Binding Update Support January 20124.2. Extensions to Proxy Binding Acknowledgment Message
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Status |K|R|P|T|B| Res.|
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Sequence # | Lifetime |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
. .
. Mobility options .
. .
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 3: Proxy Binding Acknowledgment Message
A new flag, Bulk-Binding-Update (B) flag is defined in the Proxy
Binding Acknowledgment message specified in [RFC5213]. The bit-value
of Bulk-Binding-Update (B) flag in the flags field of the message is
(IANA-2).
If the Bulk-Binding-Update flag (B) is set to a value of (1), it
serves as an indication to the mobile access gateway that the local
mobility anchor has enabled bulk binding update support for the
mobility session associated with this message. The value of the flag
MUST be set to the value of (0), if the value of the (B) flag in the
Proxy Binding Update message that it received from the mobile access
gateway was set to a value of (0).
This flag is relevant only for Proxy Mobile IPv6 and therefore MUST
be set to value of (0), when the (P) flag is set to a value of (0).
All other fields in the Proxy Binding Acknowledgment message and the
mobility options that can be carried in the message conform to the
respective specifications.
4.3. Mobile Node Group Identifier Option
A new option, Mobile Node Group Identifier option is defined for
using it in Proxy Mobile IPv6 signaling messages exchanged between a
local mobility anchor and a mobile access gateway. This option is
used for carrying the mobile node's group identifier. There can be
multiple instances of this option in a given signaling message,
however, each of the instance SHOULD have a different sub-type value.
This option is a generic option and this specification uses only the
sub-type value of (1).
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The type value for this option is (IANA-3).
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Type | Length | Sub-type | Reserved |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Mobile Node Group Identifier |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 4: Mobile Node Group Identifier Option
Type
<(IANA-3)>
Length
This is an 8-bit unsigned integer indicating the length in octets
of this option, excluding the type and length fields. The value
for this field MUST be set to a value of (6).
Sub-type
This 8-bit field identifies the specific mobile node's group type.
This number space will be managed by the IANA. The sub-type value
of (1) is reserved for Bulk Binding Update Group.
Reserved
This 8-bit field is unused for now. The value MUST be initialized
to (0) by the sender and MUST be ignored by the receiver.
Mobile Node Group Identifier This 32-bit field contains the mobile
node's group identifier. The value of (0) is reserved and SHOULD
NOT be used. The value of (1) ALL-SESSIONS, is the default group
of all mobility sessions established between a given local
mobility anchor and a mobile access gateway.
4.4. Status Codes
This document defines the following new Status codes values for use
in the Proxy Binding Acknowledgement message. These values are to be
allocated from the same numbering space, as defined in Section 6.1.8
of [RFC6275].
INVALID_MOBILE_NODE_GROUP_IDENTIFIER: (IANA-5)
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Invalid group identifier value in the request
5. Protocol Considerations5.1. MAG Considerations
The following considerations MUST be applied by the mobile access
gateway when supporting this specification.
5.1.1. Extensions to Binding Update List Entry Data Structure
The conceptual Binding Update List entry data structure maintained by
the mobile access gateway, described in Section 6.1 of [RFC5213],
MUST be extended to include the following additional fields.
o MAG-Bulk-Binding-Update-Group-Id - It is the bulk binding update
group identifier assigned by this mobile access gateway for this
mobility session. This is a 32-bit unsigned integer. This
identifier is not globally unique within a Proxy Mobile IPv6
domain, the same group identifier value may be used by other
nodes.
o LMA-Bulk-Binding-Update-Group-Id - It is the bulk binding update
group identifier assigned by the local mobility anchor for this
mobility session. This is a 32-bit unsigned integer. This
identifier is received in the Mobile Node Group Identifier option
of the Proxy Binding Acknowledgement message. This identifier is
not globally unique within a Proxy Mobile IPv6 domain, the same
group identifier value may be used by other nodes.
5.1.2. Requesting Bulk Binding Update Support for a Mobility Session
The mobile access gateway MUST apply the following considerations for
requesting bulk binding update support for a mobility session.
o When sending a Proxy Binding Update message to the local mobility
anchor, the mobile access gateway MAY choose to request the local
mobility anchor to enable bulk binding update support for the
mobility session associated with that Proxy Binding Update
request. When making such request, the Bulk-Binding-Update flag
(B) in the request MUST be set to a value of (1) and the Mobile
Node Group Identifier option MUST be present. The decision to
request the bulk binding update support for a mobile node is a
matter of local policy at the mobile access gateway and is
controlled by the configuration variable,
RequestBulkBindingUpdateSupportForMobilitySession.
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o The mobile access gateway MUST assign a bulk binding update group
identifier for the mobility session. Considerations on how the
mobile access gateway assigns a group identifier to a mobility
session is outside the scope of this document. This group
identifier can be unique to the service card on which the mobility
session is hosted, or based on other grouping considerations.
When there is no such group assignment is done, the mobile access
gateway SHOULD assign the default group identifier value of (ALL-
SESSIONS). This assigned group identifier value MUST be present
in the Mobile Node Group Identifier option and the the sub-type
value in the option MUST be set to value of (1) (bulk binding
update group).
o If the received Proxy Binding Acknowledgment message has the Bulk-
Binding-Update flag (B) in the reply set to a value of (0), this
is in response to a Proxy Binding Update request with the Bulk-
Binding-Update flag (B) set to a value of (1), it is an indication
that the local mobility anchor has denied the request for enabling
bulk binding update support for that mobility session and that the
mobility session is not associated with any bulk binding update
group. The mobile access gateway SHOULD set the bulk binding
update group identifier values, LMA-Bulk-Binding-Update-Group-Id
and MAG-Bulk-Binding-Update-Group-Id values to (0), in the Binding
Update List entry for that mobility session. Furthermore, the
mobility session should be excluded from any bulk binding update
operations.
o If the received Proxy Binding Acknowledgment message has the
status code value set to (0) (Proxy Binding Update accepted) and
the Bulk-Binding-Update flag (B) in the reply is set to a value of
(1), it is an indication that the local mobility anchor has
accepted the request to allow bulk binding update support for that
mobility session. Furthermore, the Mobile Node Group Identifier
option in the reply, with sub-type value of (1) (bulk binding
update group), contains the bulk binding update group identifier
for that mobility session assigned by the local mobility anchor.
The mobile access gateway MUST update the LMA-Bulk-Binding-Update-
Group-Id and MAG-Bulk-Binding-Update-Group-Id parameters in the
Binding Update List entry for that mobility session. However, if
the received Proxy Binding Acknowledgement message has the Bulk-
Binding-Update flag (B) set to a value of (1), but if the Mobile
Node Group Identifier option is not present, the message MUST be
considered as malformed and ignored.
o At any point of time, the mobile access gateway chooses to request
the local mobility anchor to disable bulk binding update support
for a mobility session, it MUST send a Proxy Binding Update
message with the (B) flag set to a value of (0) and the Mobile
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Node Group Identifier option MUST NOT be present. This message is
sent as a normal binding update request for lifetime extension.
Considerations from section 6.9.1 [RFC5213] MUST be applied.
Furthermore, the mobile access gateway MUST update Binding Update
List entry, by setting the bulk binding update group identifier
values, LMA-Bulk-Binding-Update-Group-Id and MAG-Bulk-Binding-
Update-Group-Id values to (0) and the mobility session MUST be
excluded from any bulk binding update operations.
5.1.3. Supporting Bulk Binding Updates
The following section identifies the considerations for mobile access
gateway for performing binding update and revocation operations with
group specific scope.
o For extending the lifetime of all mobility sessions that share the
same bulk binding update group identifier, the mobile access
gateway MAY choose to send a Bulk binding update request. For
making such request, it can send a Proxy Binding Update message to
the local mobility anchor, including the Mobile Node Group
Identifier option with sub-type value of (1) (bulk binding update
group), and with the Bulk-Binding-Update flag (B) set to a value
of (0). The identifier value in the option MUST be set to the
bulk binding update group identifier of the group for which bulk
binding update operation is being requested. The message MUST NOT
include any individual session identifiers such as, Mobile Node
Identifier option [RFC4283], Home Network Prefix option [RFC5213],
the IPv4 Home Address Request option [RFC5844], or the GRE Key
option [RFC5845]. All the Considerations from section 5.3.3
[RFC5213] MUST be followed when sending this request, with
exception related to the use of Mobile Node Group Identifier
option in place of the individual session identifiers.
o When requesting binding revocation for all the sessions that share
the same bulk binding update group identifier, the mobile access
gateway MAY choose to send a bulk revocation request. For making
such request, it can send a Binding Revocation Indication message
[RFC5846] to the local mobility anchor, including the Mobile Node
Group Identifier option, with sub-type value of (1) (bulk binding
update group). The identifier value in the option MUST be set to
the bulk binding update group identifier of the group for which
bulk binding update operation is being requested. The message
MUST NOT include any individual session identifiers such as,
Mobile Node Identifier option [RFC4283], Home Network Prefix
option [RFC5213], the IPv4 Home Address Request option [RFC5844]
or the GRE Key option [RFC5845]. All the Considerations from
section 9.2 [RFC5846] MUST be followed when sending this request,
with exception related to the use of Mobile Node Group Identifier
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option in place of the individual session identifiers.
o Any time the mobile access gateway receives a Binding Revocation
Indication message [RFC5846], with a Mobile Node Group Identifier
option present in the request and with sub-type value of (1) (bulk
binding update group), the mobile access gateway MUST consider the
request as a bulk revocation request, with the request scope for
revoking of all the mobility sessions that are part of that bulk
binding update group specific to that local mobility anchor, and
identified by the group identifier in Mobile Node Group Identifier
option.
o All the considerations from [RFC5846] apply when processing
binding revocation request, except making the scope of the
operation apply to a set of mobility sessions identified by the
bulk binding update group identifier present in the request.
o If the received Binding Revocation Indication message includes a
Mobile Node Identifier option [RFC4283], Home Network Prefix
option [RFC5213], the IPv4 Home Address Request option [RFC5844],
or the GRE Key Option [RFC5845], the mobile access gateway MUST
consider this as an invalid message; it MUST reject the Binding
Revocation Indication message and send a Binding Revocation
Acknowledgement message with the Status field set to a value of
128 (Binding Does NOT Exist).
5.2. LMA Considerations
For supporting this specification, the following considerations MUST
be applied by the local mobility anchor when processing Proxy Mobile
IPv6 signaling messages.
5.2.1. Extensions to Binding Cache Entry Data Structure
The conceptual Binding Cache entry data structure maintained by the
local mobility anchor, described in Section 5.1 of [RFC5213], MUST be
extended to include the following additional fields.
o MAG-Bulk-Binding-Update-Group-Id - It is the bulk binding update
group identifier assigned by the mobile access gateway for this
mobility session. This is a 32-bit unsigned integer. This
identifier is received in the Mobile Node Group Identifier option
of the Proxy Binding Acknowledgement message. This identifier is
not globally unique within a Proxy Mobile IPv6 domain, the same
group identifier value may be used by other nodes.
o LMA-Bulk-Binding-Update-Group-Id - It is the bulk binding update
group identifier assigned by this local mobility anchor for this
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mobility session. This is a 32-bit unsigned integer. This
identifier is not globally unique within a Proxy Mobile IPv6
domain, the same group identifier value may be used by other
nodes.
5.2.2. Enabling Bulk Binding Update Support for a Mobility Session
The local mobility anchor MUST apply the following considerations
when enabling bulk binding update support for a mobility session.
o The local mobility anchor will process a received Proxy Binding
Update message as specified in [RFC5213]. However, if the (B)
flag in the received Proxy Binding Update message is set to a
value of (1) and if it includes a Mobile Node Group Identifier
option with sub-type value of (1) (bulk binding update group), the
local mobility anchor MUST apply the following additional
considerations.
o If the (B) flag in the received Proxy Binding Update message is
set to a value of (1) and with the Mobile Node Group Identifier
option present in the request, the message serves as a request to
the local mobility anchor to enable bulk binding update support
for that mobility session.
o Upon successful processing and acceptance of the Proxy Binding
Update, the local mobility anchor MAY choose to enable bulk
binding update support for this mobility session. The decision
whether to enable bulk binding update support for that mobility
session is a matter of local policy and is controlled by the
configuration variable, AcceptBulkBindingUpdateReqMobilitySession.
o For enabling the bulk binding update support for the mobility
session, the local mobility anchor MUST associate the mobility
session to a specific bulk binding update group locally. The
specific details on how the local mobility anchor associates the
given mobility session to a specific bulk binding update group is
outside the scope of this document. The local mobility anchor MAY
choose to assign a default bulk binding update group identifier
value of (ALL-SESSIONS), indicating that all the mobility sessions
from that mobile access gateway are part of that group. The local
mobility anchor SHOULD update the bulk binding update group
identifier values in the Binding Cache entry, LMA-Bulk-Binding-
Update-Group-Id and MAG-Bulk-Binding-Update-Group-Id to the
respective values.
o If the bulk binding update support is enabled for the mobile
node's mobility session, the local mobility anchor MUST send the
assigned bulk binding update group identifier as part of the
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Mobile Node Group Identifier option, with sub-type value of (1)
(bulk binding update group) in the Proxy Binding Acknowledgment
message that it sends to the mobile access gateway. The (B) flag
in the Proxy Binding Acknowledgment message MUST be set to value
of (1).
o If the bulk binding update support is not enabled for the mobility
session, the local mobility anchor MUST NOT include the Mobile
Node Group Identifier option with a sub-type value of (1) (bulk
binding update group), in the Proxy Binding Acknowledgment message
that it sends to the mobile access gateway. Furthermore, the (B)
flag in the Proxy Binding Acknowledgment message MUST be set to
value of (0). It is to be noted that the Mobile Node Group
Identifier option is a generic option and new sub-types may be
defined by future specifications.
o If the received Proxy Binding Update message is not a bulk binding
update request, (i.e., the (B) flag is set to a value of (0) and
the Mobile Node Group Identifier option with sub-type value of (1)
(bulk binding update group) is not present), but is a request for
extending the lifetime of an existing mobility session, for which
the bulk binding update support is already enabled, then the local
mobility anchor MUST process the request as specified in
[RFC5213]. However, the value of (0) in the (B) flag in the
message serves as a request for the local mobility anchor to
disable bulk binding update support for that mobility session.
Upon accepting the request, the local mobility anchor SHOULD set
the parameters, LMA-Bulk-Binding-Update-Group-Id and MAG-Bulk-
Binding-Update-Group-Id in the Binding Cache entry to a value of
(0) and the mobility session MUST be excluded from any bulk
binding update operations.
o Any time the local mobility anchor detects that the mobile node
has roamed and changed its point of attachment to a new mobile
access gateway, it SHOULD also update the bulk binding update
group identifier of the mobility session. Additionally, it should
also update the existing group identifiers associated with that
session. As part of sending the Proxy Binding Acknowledgment to
the new mobile access gateway, it MUST include the updated group
identifier in the Mobile Node Group identifier option, with a sub-
type value of (1). However, if the if the received Proxy Binding
Update from the new mobile access gateway did not have the (B)
flag set to a value of (1), then it MUST NOT include the mobility
session in any of bulk binding update group and MUST NOT include
the Mobile Node Group identifier option with the sub-type value of
(1).
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o Any time a mobile node's mobility session is de-registered by the
mobile access gateway, or the session is revoked for
administrative or any other reasons, the mobility session MUST
also be removed from the bulk binding update group.
5.2.3. Supporting Bulk Binding Updates
The following section identifies the considerations for local
mobility anchor for performing binding update and revocation
operations with group specific scope.
o Any time the local mobility anchor receives a Proxy Binding Update
message with the (B) flag in the request is set to a value of (0)
and if a Mobile Node Group Identifier option present in the
request and with sub-type value of (1) (bulk binding update
group), the local mobility anchor MUST consider the request as a
bulk binding update request, with the request scope for all the
mobility sessions that are part of that bulk binding update group,
specific to that mobile access gateway, and identified by the
group identifier in Mobile Node Group Identifier option. However,
if the received request also includes any individual session
identifiers such as, Mobile Node Identifier option [RFC4283], Home
Network Prefix option [RFC5213], the IPv4 Home Address Request
option [RFC5844], or the GRE Key option [RFC5845] the local
mobility anchor MUST consider this as an invalid message; it MUST
reject the Proxy Binding Update message and send a Proxy Binding
Acknowledgement message with the Status field set to
INVALID_MOBILE_NODE_GROUP_IDENTIFIER (Invalid group identifier
value in the request).
o The local mobility anchor MUST consider the message as a request
for extending the lifetime of all the mobility sessions that are
associated to each of group identifier from the Mobile Node Group
Identifier option. However, if the Mobile Node Group Identifier
option, with sub-type value of (1) (bulk binding update group),
has an unknown group identifier, then the local mobility anchor
MUST reject the Proxy Binding Update message and send a Proxy
Binding Acknowledgement message with the Status field set to
INVALID_MOBILE_NODE_GROUP_IDENTIFIER (Invalid group identifier
value in the request).
o Upon accepting the bulk binding update request, the local mobility
anchor SHOULD extend the lifetime for all the mobility sessions
that are part of bulk binding update group identified by the group
identifier in the Mobile Node Group Identifier in the message.
Considerations from [RFC5213] MUST be applied for extending the
lifetime of a mobile node's session. It MUST also send a Proxy
Binding Acknowledgment message with the Status field value set to
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0 (Proxy Binding Update accepted). The lifetime field in the
message MUST be set to the allocated lifetime for all the mobility
sessions. The message MUST also include the Mobile Node Group
Identifier option, with sub-type value of (1) (bulk binding update
group), with the identifier value copied from the Mobile Node
Group Identifier option present in the received Proxy Binding
Update message.
o If the local mobility anchor rejects the bulk binding update
request for any administrative reason, then it MUST NOT update the
lifetime in the binding cache entries of any of the mobile nodes
identified by the group identifier. The local mobility anchor
SHOULD send a Proxy Binding Acknowledgment indicating the reason
for the rejection in the status code.
o Any time the local mobility anchor receives a Binding Revocation
Indication Message [RFC5846], with a Mobile Node Group Identifier
option present in the request and with sub-type value of (1) (bulk
binding update group), the local mobility anchor MUST consider the
request as a bulk revocation request, with the request scope
including all the mobility sessions that are part of that bulk
binding update group, specific to that mobile access gateway, and
identified by the group identifier in Mobile Node Group Identifier
option. However, if the received request also includes a Mobile
Node Identifier option [RFC4283], Home Network Prefix option
[RFC5213], the IPv4 Home Address Request option [RFC5844], or the
GRE Key Option [RFC5845], the local mobility anchor MUST consider
this as an invalid message; it MUST reject the Binding Revocation
Indication message and send a Binding Revocation Acknowledgement
message with the Status field set to a value of 128 (Binding Does
NOT Exist). All the considerations from [RFC5846] apply when
processing binding revocation request, except making the scope of
the operation apply to a set of mobility sessions identified by
the group identifier present in the request.
o Upon accepting the Binding Revocation Indication request and
completing the operation, the local mobility anchor MUST send a
Binding Revocation Acknowledgement message with the Status field
set to a value of 0 (success). The message MUST include the
Mobile Node Group Identifier option, with the identifier value
copied from the Mobile Node Group Identifier option present in the
received Binding Revocation Indication message.
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Internet-Draft Bulk Binding Update Support January 20126.1. Local Mobility Anchor - Configuration Variables
The local mobility anchor MUST allow the following variables to be
configured by the system management. The configured values for these
protocol variables MUST survive server reboots and service restarts.
AcceptBulkBindingUpdateReqMobilitySession
This flag indicates whether or not the local mobility anchor
should accept the request from the mobile access gateway to enable
bulk binding update support for the mobility session. The default
value for this flag is set to (1), indicating that it SHOULD
accept the request from the mobile access gateway. If the value
of the flag is set to (0), the local mobility anchor MUST deny the
request.
6.2. Mobile Access Gateway - Configuration Variables
The mobile access gateway MUST allow the following variables to be
configured by the system management. The configured values for these
protocol variables MUST survive server reboots and service restarts.
RequestBulkBindingUpdateSupportForMobilitySession
This flag indicates whether or not the mobile access gateway
should request the local mobility anchor to enable bulk binding
update support for the mobility session. The default value for
this flag is set to (1), indicating that the the mobile access
gateway MUST set the bulk binding update flag (B) in the Proxy
Binding Update request to a value of (1). If the flag is set to a
value of (0), the mobile access gateway MUST set the bulk binding
update flag (B) in the Proxy Binding Update to a value of (0).
7. IANA Considerations
This document requires the following five IANA actions.
o Action-1: This specification defines a new flag (B) to the Proxy
Binding Update message, specified in [RFC5213]. This flag is
described in Section 4.1. The value of the flag (B) needs to be
allocated from the Binding Update Flags registry.
o Action-2: This specification defines a new flag (B) to the Proxy
Binding Acknowledgment message, specified in [RFC5213]. This flag
is described in Section 4.2. The value of the flag (B) needs to
be allocated from the Binding Acknowledgment Flags registry.
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o Action-3: This specification defines a new Mobility Header option,
the Mobile Node Group Identifier option. This option is described
in Section 4.3. The Type value for this option needs to be
assigned from the same numbering space as allocated for the other
mobility options [RFC6275].
o Action-4: The Sub-type field of the Mobile Node Group Identifier
option introduces a new number space. This number space needs to
be managed by IANA, under the Registry, Mobile Node Group
Identifier Type Registry. This specification reserves the sub-
type value of (1) (Bulk Binding Update Group). Approval of new
sub-type values are to be made through IANA Expert Review.
o Action-5: This document also defines a new status value
INVALID_MOBILE_NODE_GROUP_IDENTIFIER (Invalid group identifier
value in the request: IANA-5) for use in Proxy Binding
Acknowledgement message, as described in Section 4.4. This value
is to be assigned from the same number space as allocated for
other Status codes [RFC6275]. The allocated value has to be
greater than 128.
8. Security Considerations
The Mobile Node Group Identifier option defined in this specification
is for use in Proxy Binding Update and Proxy Binding Acknowledgement
messages. This option is carried like any other mobility header
option and it does not require any other special security
considerations.
The bulk binding update and the bulk revocation operations specified
in this document, perform operations on a group of mobility sessions.
If proper authorization checks are not in place, a malicious node may
be able to hijack a mobile node's mobility session or may carry out a
denial- of-service attack. To prevent this attack, this
specification requires the local mobility anchor to allow only
authorized mobile access gateways to perform bulk operations.
9. Acknowledgements
The authors would like to specially thank Jouni Korhonen, Basavaraj
Patil, Carlos Jesus Bernardos Cano, Dirk Von-Hugo, and Jari Arkko for
their reviews and inputs to this document.
10. ReferencesAbinader, et al. Expires July 13, 2012 [Page 21]